Conventionally, a refrigerant circulated in the lines of a large refrigerating machine or air conditioner functions in transferring heat energy to a compressor and so on. Referring to FIG. 1, a typical refrigeration system comprises a compressor 1 for compressing refrigerant, a condenser 2 for receiving the high-pressure, high-temperature refrigerant from the compressor 1 and cooling it into a refrigerant having a temperature approximately equal to atmospheric temperature, an expansion valve 4 and an evaporator 5 for receiving the atmospheric temperature refrigerant from the condenser 2 and vaporizing it to achieve a refrigeration effect. Further, it is often necessary to provide a cooling tower 3 in fluid communication with the condenser 2 for quickly lowering the temperature of the refrigerant. However, providing the cooling tower 3 consumes additional energy. From another aspect, while equipped with the cooling tower 3, such a typical refrigeration system is still disadvantageous due to the lengthy temperature-lowering process. To make it worse, only the refrigeration effect is somewhat satisfied, while energy is not effectively utilized in the refrigeration cycle as a whole.
Traditionally, a person uses a heater powered by gas or electricity to heat cold water to a desired high temperature for a predetermined time. One may think that if one can use latent energy not utilized by the refrigeration system to heat the cold water to an intermediate temperature such that then one can use such warm water directly from the tap in daily life. Alternatively, if higher temperature water is desired, one can use also a heater to heat the warm water to the desired high temperature. The design of the present invention is aimed at utilizing such latent energy for increasing the thermal efficiency of a refrigeration system.